The present invention relates to self-latching hinges, and particularly to a hinge that develops its spring force by stressing one of the hinge members itself.
Self-latching hinges have gained substantial acceptance in the building industry for the reason that separate latch hardware is obviated. Self-latching hinges are quite old. U.S. Pat. No. 2,145,689 to Hanle shows a box closure utilizing an overcenter cam and leaf spring arrangement. U.S. Pat. No. 2,522,997 to Rotter shows a lens cover that utilizes a coil spring and a latching recess. The principle of such self-latching hinges has been applied to cabinets. The basic problem is to develop an adequate spring force sufficient to operate a relatively massive cabinet door. A successful structure is shown and described in U.S. Pat. No. 3,205,532 to MacDonald. The MacDonald structure utilizes a strong prestressed spring that is captured in one of the hinge members. The spring urges a roller against the hinge knuckle of the companion hinge member and into a recess that begins to register with the roller when the companion hinge member approaches closed position. A high torque is imposed notwithstanding the small lever arm by virtue of the fact that the spring is very strong.
The problem with the MacDonald structure is that the spring is not easily assembled. Complicated fixtures are required. The basic object of the present invention is to provide a very simple self-closing hinge structure that generates a very substantial closing force without requiring any prestressed or other springs.